Inside the SPS tunnel at LSS3

<!--HTML-->The image shows part of LSS3 of the SPS. Towards the left there is one of the two 800 MHz travelling wave structures of the SPS shown. Downstream follow three of the four 200 MHz travelling wave structures. Only the first of those three structures can be clearly seen. <p>The 200 MHz travelling wave structures are the main accelerating cavities of the SPS. The two 800 MHz travelling wave structures were installed to suppress by means of Landau damping existing longitudinal instabilities and those expected with the increase of the SPS intensity.